The signal box after the last train

Text: an original contemporary railway-account-style practice extract.

The signal box had closed after the last passenger train, but I climbed the wooden stairs to collect the notebook I had left beside the timetable. Rain had stopped. At the far window, a loose shutter knocked once in the wind. I could see its edge tremble, although the rest of the room lay beyond the desk lamp's reach. I waited for the sound to return, annoyed that I was waiting.

The levers stood in a row, their painted numbers worn pale where hands had used them. A red signal outside cast a narrow bar across the floorboards. When a train moved through the valley, the light disappeared and the room seemed to lose its only fixed point. My notebook was open at a page I did not remember choosing. The handwriting was mine, but the final sentence stopped after the words, “When the signal...” I decided that I must have been interrupted earlier and forgotten. Even so, the unfinished line made the silence around it feel deliberate.

I put the notebook in my bag and began to descend. From above came the dry sound of several pages being turned. The shutter was still and the window was closed. I did not climb back to find the cause. I opened the door and stepped out into the wet night, leaving the signal box to its darkness.

In this extract, the writer tries to create an atmosphere of unease.

Evaluate how successfully this is achieved. Support your views with detailed reference to the extract.